Television pictures are subject to variation in quality, for example color saturation and tint, due to less than ideal or inconsistent studio and production, signal processing and transmission conditions. These conditions are caused, for example, by improper lighting conditions, improper signal conditioning following recording, poor transmission, low quality signal demodulation in the receiver, or imperfect camera work.
Variation in picture quality can also be caused by improper picture settings at the receiver. Viewers can compensate for selected picture "imperfections" (i.e. in color, tint, brightness, contrast) using the receiver controls available to adjust these parameters. VIR reference signals transmitted along with the program signal can also be utilized by a properly equipped television receiver, to help adjust for transmission based inconsistencies in the picture. Unfortunately however, since the causes and degree of picture quality variation can change from program to program and scene to scene, the viewer usually has a choice of either putting up with the variations not correctable using VIR systems, or adjusting the receiver controls with each change in picture quality. In addition, VIR based systems require the broadcasters to agree to send the VIR signal and fail to address differences in the transmission medium or defects in the receiver.
The use of rule based "fuzzy logic" to control electronic apparatus has been described, for example, in U.S. Pat. No. 4,864,490, incorporated by reference herein. This patent describes a system for process control using predetermined reasoning rules. Computer software architecture for performing rule based reasoning and analysis is discussed in U.S. Pat. No. 4,918,620 which is also incorporated by reference herein. Such software is commercially available, for providing a decision system shell. Such a software package is commercially available under the name "CubiCalc".
The use of neural networks (nets) to simultaneously process information inputs in a non-linear system, to provide a solution, are well known in the information processing art. References describing such neural nets, their applications and implementation, include "An Introduction to Computing With Neural Nets", Lippmann, IEEE, ASSP Magazine, Apr. 7, 1987 and "Analogue Circuits for Variable-Synapse Electronic Neural Networks", Tsividis & Satyanarayana, Electronic Letters, Nov. 19, 1987", as well as U.S. Pat. No. 4,866,645, which are incorporated by reference herein.
The instant invention has as its object, to provide a system for automatically improving the picture quality of television or other video based images, based upon picture content, using improved rule based picture analysis and compensation techniques. The embodiments decribed herein can be implemented, for example in a VLSI chip to provide a cost effective and robust implementation (i.e. one not substantially effected by fabrication variations).